1. Field of the Invention
The present invention relates to a method and a circuit for power switching, more particularly, a method and a circuit for seamless power switching, which is used to save chip power-consumption and protect related circuits.
2. Description of the Prior Arts
On the premise of environment protection, saving power is inevitable with the uprising need for it in electrical equipment. The power supply element has optimal power supply range for corresponding different requirements of power consumption, and the power supply element also may set function of saving power according to the requirements of function.
The setting of electricity-saving function is divided to two types: power setting and non-power setting. The early saving power mechanism is mainly based on the non-power setting, for example, clock division, decreasing or shutoff clock; the modern saving power mechanism is mainly based on power setting, for example, power division, lowering voltage, or shutoff power. However, this setting of electricity-saving function still has some localization.
Accordingly, in view of the above drawbacks, the inventor of the present application provides two different rated consuming power sources according to chip operation, and the chip is switched to low power consumption output source for saving power when the low power consumption is required. However, the circuit must keep in normal operation (seamless power supply) when the different sources are alternately switched, resulting in it is difficult to maintain the voltage level and switch smoothly, and the large current generated will damage the power supply elements.
Moreover, in view of the above drawbacks, the present invention further provides a method and a apparatus for power switching, more particularly, a method and a circuit for seamless power switching, which is used to save chip power-consumption and protect related circuits, improves some problems, such as overcurrent generated from power switching will damage the power supply chips or the bias sources.